And it's more than just an effect of infrared imaging. If you duck over to Joseph Stromberg's post at the Surprising Science blog, you'll see a photo of a real, live reindeer with an adorably red nose (and upper lip).

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It's true! Science proves it!

And it's more than just an effect of infrared imaging. If you duck over to Joseph Stromberg's post at the Surprising Science blog, you'll see a photo of a real, live reindeer with an adorably red nose (and upper lip).

Turns out, it's the result of an evolutionary adaptation. Some (but not all) reindeer have noses full of densely packed blood vessels — a difference that makes those reindeer better at regulating their own body temperatures.

To come to the findings, the scientists examined the noses of two reindeer and five human volunteers with a hand-held video microscope that allowed them to see individual blood vessels and the flow of blood in real time. They discovered that the reindeer had a 25% higher concentration of blood vessels in their noses, on average.

They also put the reindeer on a treadmill and used infrared imaging to measure what parts of their bodies shed the most heat after exercise. The nose, along with the hind legs, reached temperatures as high as 75°F—relatively hot for a reindeer—indicating that one of the main functions of all this blood flow is to help regulate temperature, bringing large volumes of blood close to the surface when the animals are overheated, so its heat can radiate out into the air.

Also: red-nosed reindeer on treadmills, you guys. This is clearly the most adorable science of the holiday season.